WEDNESDAY, Jan. 4 (HealthDay News) -- Small but continued drops in cancer incidence and deaths in the United States in recent years are charted in a new report.

Between 2004 and 2008, death rates for cancer went down by 1.8 percent a year in men and 1.6 percent a year in women, the American Cancer Society (ACS) reported Wednesday.

And from 1990 through 2008, death rates plunged almost 23 percent for men and just over 15 percent for women.

"Cancer death rates in the U.S. have continued to decrease since the early 1990s," said Dr. Ahmedin Jemal, senior author of the new report, published online Jan. 4 in CA: A Cancer Journal for Clinicians. "As a result of this, about a million cancer deaths were averted."

The decreases, said Jemal, who is vice president for surveillance research at the ACS, "largely reflect improvements in prevention, early detection and treatment."

The annual report is based on the most recent data available from the National Cancer Institute and the U.S. Centers for Disease Control and Prevention.

Death rates dropped most dramatically among black men (2.4 percent per year) and Hispanic men (2.3 percent annually).

"It's an encouraging note that the decrease in cancer deaths was a little larger as a percentage in the African-American population," said Dr. Michael V. Seiden, president and CEO of Fox Chase Cancer Center in Philadelphia. "This is wonderful to see because, as a group, they do much worse than whites. That's a gap we need to close."

The report also noted continued advances were made against the four major cancer killers -- lung, colorectum, breast and prostate. Declines in lung cancer deaths accounted for almost 40 percent of the total decline in men, and longer lives among breast cancer survivors resulted in 34 percent of the total drop in women.

Meanwhile, cancer incidence rates dipped 0.6 percent for men, although they remained unchanged for women.

There was also good news in the area of childhood malignancies. Although incidence increased by half a percent from 2004 to 2008, death rates since 1975 have decreased from 4.9 per 100,000 children to 2.2 per 100,000 in 2008. The five-year survival rate is now 83 percent, up dramatically from 58 percent in the mid-1970s, the report found.

Still, one in four deaths in the United States each year is due to cancer and, in 2012, some 1.6 million new cancers will be diagnosed and almost 600,000 people will die from the disease.

Racial and ethnic disparities remain, with black men and women more likely to get cancer and more likely to die from it.

And there have been disconcerting increases in cancers of the pancreas, liver, thyroid and kidney as well as melanoma, esophageal adenocarcinoma and some oropharyngeal cancers, the last related to infection with human papillomavirus (HPV).

"These are worrisome trends which require further study and intervention," said Seiden.

Experts don't really know the reasons behind these increases but some, such as cancers of the kidney and pancreas, may be related to the growing obesity epidemic, said Jemal.

The rise in liver tumors could well be due to hepatitis C infections or intravenous drug use in the 1960s and '70s, he added.

Much additional progress is easily within reach, said Seiden.

"There's still a lot of low-lying fruit. Still, only half our population is getting screened by colonoscopy, 20 percent smoke cigarettes. Mammography, Pap screening, all of those have room for an upside as do vaccinations for things like HPV and hepatitis," he said. "There is still plenty of incremental improvement in earlier diagnosis, in cancer prevention and, of course, in extending lives through better cancer therapies."

More information

The American Cancer Society has more on cancer.